Preheat your oven to 325 degrees F. This ensures a consistent baking temperature. While it’s heating, gather your tools and ingredients.
Butter two 9-inch round cake pans. This will help the cake release easily after baking. Line the bottoms with parchment paper, butter the parchment too, and dust lightly with flour to prevent sticking.
In a mixing bowl, whisk together flour, baking soda, and salt for about 30 seconds. This helps to evenly distribute the leavening agent throughout the flour.
In another bowl, mash your bananas with lemon juice. The lemon juice enhances the banana flavor and prevents browning.
In the bowl of an electric stand mixer fitted with a paddle attachment, whip together butter, vegetable oil, granulated sugar, and light brown sugar on medium-high speed until the mixture is pale and fluffy. This can take about 2 to 3 minutes.
Beat in the eggs one at a time, making sure to fully incorporate each before adding the next. This step is crucial for creating a light texture in your cake.
Add in vanilla and the mashed bananas, stirring until everything is just combined.
With the mixer set on low speed, slowly add the flour mixture alternately with buttermilk in three separate batches, starting and ending with the flour mixture. Mix just until combined after each addition; overmixing can lead to a tough cake.
Divide the batter evenly between the prepared cake pans, smoothing the tops with a spatula as needed. This ensures even baking.
Bake in the preheated oven for 45 to 50 minutes, or until a toothpick inserted into the center comes out clean. Allow the cakes to cool completely in the pans.
While the cakes are cooling, prepare the Whipped Cream Cheese Frosting. In the bowl of an electric mixer fitted with a whisk attachment, whip heavy cream on high speed until stiff peaks form. Transfer to a separate bowl and set aside.
Switch back to the paddle attachment, add cream cheese and butter into the stand mixer, and whip together until smooth and fluffy, about 2 minutes, scraping down the sides as necessary.
Gradually add in powdered sugar and vanilla, whipping on medium speed for an additional 2 minutes until combined.
Fold half of the whipped cream into the cream cheese mixture until well combined. Gently fold in the remaining whipped cream, taking care not to deflate it.
Spread the frosting generously over the cooled cake layers, stacking them if desired. Keep the cake cool until ready to serve.